// streams/FunctionMap.java
// (c)2017 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.

import java.util.Arrays;
import java.util.function.Function;
import java.util.stream.Stream;

class FunctionMap {
    static String[] elements = {"12", "", "23", "45"};

    static Stream<String> testStream() {
        return Arrays.stream(elements);
    }

    static void
    test(String descr, Function<String, String> func) {
        System.out.println(" ---( " + descr + " )---");
        testStream()
                .map(func)
                .forEach(System.out::println);
    }

    public static void main(String[] args) {

        test("add brackets", s -> "[" + s + "]");

        test("Increment", s -> {
            try {
                return Integer.parseInt(s) + 1 + "";
            } catch (NumberFormatException e) {
                return s;
            }
        });

        test("Replace", s -> s.replace("2", "9"));

        test("Take last digit", s -> s.length() > 0 ?
                s.charAt(s.length() - 1) + "" : s);
    }
}
/* Output:
 ---( add brackets )---
[12]
[]
[23]
[45]
 ---( Increment )---
13

24
46
 ---( Replace )---
19

93
45
 ---( Take last digit )---
2

3
5
*/
